BACKGROUND: There are no large-scale epidemiological studies on primary hyperparathyroidism (PHPT) in Russia. The high prevalence of the disease, the high risk of disability and death in this cohort of patients requires the study of the epidemiological and clinical structure of PHPT to determine the extent of medical care. AIM: Evaluate the frequency of PHPT detection and characterize its clinical forms in Russia using an online registry. METHODS: The object of the study is the database of the State Register of Patients with PHPT 1914 patients from 71 regions of the Russian Federation. New cases of the disease, as well as dynamic indicators are recorded when patients visit outpatient clinics or medical institutions. The analysis of data made at the end of December 2017 was carried out. The following parameters were evaluated: demographic and clinical indicators; indicators of phosphorus-calcium metabolism, the main forms of PHPT and its course, the primary characteristic of PHPT in hereditary syndromes and parathyroid carcinoma. Results are presented as mean and standard deviations, or medians and quartiles; descriptive statistics of qualitative attributes absolute and relative frequencies. RESULTS: the total number of patients with PHPT in the registry on 31 of December 2017 was 1914 cases (0.001% of the population of the Russian Federation). Identification of PHPT was 1.3 cases per 100 thousand of the population in Russia, 7.6 cases in Moscow, 6.1 cases per 100 thousand in the Moscow region. The average age of patients at the time of diagnosis was 55.6 10 years. The active phase of the disease was registered in 84.6% of patients (1620/1914), most of whom had a symptomatic PHPT 67.1% (1087/1620), and 32.9% a asymptomatic disease (533/1620). Symptomatic disease with visceral complications was detected in 15.8% cases (172/1087), with bone complications in 48.4% (526/1087). The mixed form of the disease was detected in 35.8% of patients with manifest form (389/1087). Normocalcemic variant PHPT (nPHPT) was registered in 14.5% cases (234/1620). Sporadic PHPT occurs in 83% of cases (1592/1914). 326 patients (17%) had a suspicion for hereditary form of the disease: average age was 31.2 12.3 years. A genetic analysis was conducted in 61 patients (3.2%): showed the mutation in the MEN1 gene in 2.9% of cases (55/1914) and the mutation in the CDC73 gene in 0.3% of cases (6/1914) (HPT-JT syndrome). Parathyroid carcinoma was confirmed in 1.8% of all patients (35/1914). Surgical treatment was performed in 64.5% of patients (1234/1914). Remission was achieved in 94% of cases (1160/1234), in 6% of cases relapse after surgical treatment or persistence of PHPT was recorded. CONCLUSION: detection of PHPT in the Russian Federation raised in comparison to 2016, which is associated with an active start of registration of patients in the regions. At this stage, it is necessary to modify the principles of registration and control, to make a platform for gathering information and calculating the necessary volumes of medical care for PHPT patients.

To elucidate specific features of epidemiology of various forms of primary hyperparathyroidism (PHPT) in this country using the information about 561 patients accumulated for 19 years in the database of Federal state institution «Endocrinological Research Centre». The incidence of PHPT in Moscow estimated from the database of Endocrinological Research Centre for 2007 was 6.8 per 1 000 000 adult population and the prevalence as per 2009 was 3.1/100 000. These values are significantly lower than those reported by foreign authors. The men to women ratio among the patients with PHPT was 1:8. The disease largely affects subjects at the age from 50 to 60 years. By the year of 2004, the frequency of the mild form of PHPT did not exceed 20% of the total (based on 2002 Consensus criteria). It increased to 37% during the past 5 years. Conservative treatment of PHPT can be recommended to 14% of the patients presenting with sporadic disease and to 32% of those with MEN syndrome. The frequency of asymptotic PHPT and its normocalcemic forms is estimated at 5% and 9% respectively. The above results are the first data on epidemiology of PHPT in this country; however, they are insufficient to comprehensively evaluate the real significance of the problem. Large-scale epidemiological studies are needed to ensure adequate assessment of the situation.

The view of the clinical picture of primary hyperparathyroidism (PHPT) has essentially changed during the recent years under the influence of new data about its prevalence and the structure of the disease. The analysis of the database created at the Endocrinological Research Centre and including 1053 patients was used to obtain an epidemiological characteristics of various forms of PHPT recorded in Russia. PHPT morbidity in Moscow was estimated, based on the incidence of outpatient visits, to reach 0.05 per 1,000 adult population. This figure is significantly lower than that reported in foreign publications. The manifest form appears to be the most widespread form of PHTP in this country. The relative prevalence of the mild form has increased in the last years (till 2012) but does not exceed 28% or significantly lower than abroad where it is reported to prevail in the structure of PHPT morbidity. The asymptotic form accounts for 7.5% of all PHPT cases in the framework of type 1 multiple endocrine neoplasia syndrome (MEN-1) where it most frequently occurs in combination with pituitary adenomas (81%), in the first place prolactinomas, somatotropinomas, and pancreatic tumours (45%).